The Hammer Falls

If you've been following this guide and doing all the quests, you should be pushing level 20 and in good shape to take on this climactic battle. Make your way to the entrance to Headstone Mine.

This is basic urban combat for the most part. It's easy to retreat and take cover. Near the exit of the first camp there's a sniper up above. Nearby on the north side, there's a building with a weapons chest that you should definitely check out.

The next area is a bit harder. There's a gun turret in the west that you can't effectively take out at long range, so scope it out and stay aware of it while sniping. Make your way into the building in the west (there's a weapons chest and lots of loot here) and then make your way up the steps where you can hit the turret with grenades and seek cover. A bit east of here on the upper level you can find a red chest in a building, or follow the tracks the other way to continue.

Down below, you'll fight a handful of enemies and find a gate that opens as you approach. Pass through this with caution and retreat when your health gets depleted. Go up to the second floor of the building here for a perfect sniping position. You won't be able to clear out all the bandits from here, but you will be relatively safe, able to take cover, and have a great shot of most of the battlefield, so that when you do go down below, you'll just be playing cleanup.

The fight under the tracks is a bit harder to do close range, because there isn't great cover, so consider sniping and luring enemies out into a better area. Before the narrow approach to your destination, there's a room with a red chest full of shields. There's a lift in this building that will take you to the top floor where there's a checkpoint and some vending machines. Get ready for a boss fight.

You can open either door to get to the hall where you fight Sledge. Sledge has a mean shield that you'll need to breakthrough. Luckily you were good boys and girls and you did the Shock Crystal Harvest mission, right? This should have netted you a lightning artifact and a lighting weapon. Attacks with this element will drop his shields real quick. Once his shield is down, you'll find he's still very resilient. Since he has a powerful close range shockwave attack, use a powerful long distance weapon. We had good luck firing a sniper rifle from the hip, but you may prefer rockets or combat rifles. Cover is important to recover your shields, and luckily there are plenty of places to run, but the number of other enemies milling about can make it harder, so try to take these guys out quickly by doing a sweep of the area.